1. Field of the Invention
This invention relates to a control system for processing machinery, and particularly to a control system which can control a diecast machine, etc. even in a case where the controller of the diecast machine and a sequencer have been manufactured by different manufacturers.
2. Description of the Background Art
When a plurality of diecast machines are to be controlled, the control is performed by connecting a sequencer to a diecast controller, and by connecting the plurality of diecast machines to the sequencer. In this case, a manufacturer of the sequencer is not necessarily the same as a manufacturer of the diecast controller, and as a result their specifications may be different from each other.
Conventionally, the diecast controller and the sequencer are connected by a plurality of wires between corresponding input/output terminals of the diecast controller and those of the sequencer, as shown in FIG. 5. In this case, since corresponding terminals assigned for signals are connected one by one, a secure connection can be accomplished even when the diecast controller and the sequencer have been manufactured by different manufacturers, provided that signal levels of the diecast controller and of the sequencer are the same.
However, if number of apparatuses and consequently number of terminals increases, number of wires to be connected also increases. Therefore, if a system including a lot of diecast machines is to be constructed, number of wires connecting the diecast controller with the sequencer will be enormous, and as a result, cost of wirings will be rapidly increased and reliability of connections will be decreased due to increase of possibility of miswiring.
In order to solve such a problem, it may be possible to raise workability by preparing an exclusive cable connecting the diecast controller and the sequencer in advance and by connecting both apparatuses with the cable. However, such method needs a lot of preparation time for making cables and there exists still possibility of occurrence of miswiring.
Furthermore, for other case where the number of diecast machines increases, it is usual to provide in the diecast controller a serial communication port based on the RS232C standard which is a standard regulation for the serial communication, and data is serially transmitted from the serial communication port to a serial communication port of the sequencer through an RS232C communication cable.
However, since such data transmission is a serial data transmission having a low data transmission rate, there is a problem in which it can not follow fast real time operations.